Link click temporarily freezes game

Please note: this only works in multiplayer as far as i am aware

When the 'Yes' button is clicked on the security warning for links, minecraft hangs temporarily and the link is not opened. Furthermore, I sometimes recieve a crash in the seconds afterwards.

I was hoping that my browser opened and displayed the link

Steps to re-create:
1: type a link into chat (optional)
2: Click a link
3: Press yes on the security warning

Game log (pastebin): http://pastebin.com/TNBk8yjV